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Geologic units in Alabama (state in United States)

[Additional scientific data in this geographic area]

Alluvial, coastal and low terrace deposits (Holocene) at surface, covers 13 % of this area
Alluvial, coastal and low terrace deposits - Varicolored fine to coarse quartz sand containing clay lenses and gravel in places. Gravel composed of quartz and chert pebbles and assorted metmorphic and igneous rock fragments in streams near the Piedmont. In areas of the Valley and Ridge province gravel composed of angular to subrounded chert, quartz, and quartzite pebbles. Coastal deposits include fine to medium quartz sand with shell fragments and accessory heavy minerals along Gulf beaches and fine to medium quartz sand, silt, clay, peat, mud and ooze in the Mississippi Sound, Little Lagoon, bays, lakes, streams, and estuaries.
Lithology: beach sand; alluvium
Pride Mountain Formation (Mississippian) at surface, covers 0.5 % of this area
Pride Mountain Formation - Medium to dark-gray shale, containing one to three units of a variable combination of sandstone and limestone in the lower part; locally contains rare interbeds of dusky-red and greenish-gray mudstone.
Lithology: shale; limestone; sandstone; mudstone
Chepultepec and Copper Ridge Dolomites undifferentiated (Ordovician-Cambrian) at surface, covers 0.4 % of this area
Chepultepec and Copper Ridge Dolomites undifferentiated - Light-gray to dark-bluish-gray thick-bedded dolomite and interbedded light-gray limestone; includes abundant chert.
Lithology: dolostone (dolomite); limestone; chert
Sequatchie Formation (Ordovician) at surface, covers < 0.1 % of this area
Sequatchie Formation - Grayish-red, grayish-green, and yellowish-gray thin-bedded calcareous shale and calcareous mudstone containing interbedded fossiliferous limestone, and medium-gray to moderate-red partly sandy and glauconitic, medium to coarse-grained bioclastic limestone.
Lithology: shale; mudstone; limestone
Selma Group; Demopolis Chalk (Cretaceous) at surface, covers 2 % of this area
Demopolis Chalk - (Selma Group), Light-gray to medium-light-gray compact, brittle chalk overlain by abundantly fossiliferous chalky marl, very clayey chalk, and calcareous clay (Bluffport Marl Member). In south-central Montgomery County the Demopolis is split into two eastward extending tongues by a westward-extending tongue of the Cusseta Sand Member of the Ripley Formation. The lower tongue is pale-olive to yellowish-gray silty to finely sand, micaceous, fossiliferous chalk that eastward becomes more sandy and merges with the Cusseta in central Bullock County. The upper tongue is yellowish-gray clayey, very finely sandy, micaceous chalk that merges with the Ripley in southeastern Montgomery County.
Lithology: carbonate; clay or mud; sand
Ketchepedrakee Amphibolite (Precambrian to Paleozoic) at surface, covers 0.1 % of this area
Ketchepedrakee Amphibolite - dark-green to black fine to coarse-grained, layered to massive amphibolite mixed with zones of chlorite actinolite schist, includes all amphibolite associated with the Poe Bridge Mountain Group.
Lithology: amphibolite; schist
Attalla Chert Conglomerate Member of the Chickamauga Limestone (Ordovician) at surface, covers < 0.1 % of this area
Attalla Chert Conglomerate Member of the Chickamauga Limestone - conglomerate of pebbles, cobbles, and boulders of chert and rare dolomite and quartzite in a sand-sized chert and quartz matrix; thin beds of gray-green or dusky-red shale common at base.
Lithology: conglomerate; chert; shale; dolostone (dolomite); quartzite
Claiborne Group; Tallahatta Formation (Eocene) at surface, covers 2 % of this area
Tallahatta Formation - (Claiborne group), White to very light-greenish-gray thin-bedded to massive siliceous claystone; interbedded with thin layers of fossiliferous clay, sandy clay, and glauconitic sand and sandstone. White to light-greenish-gray fine to coarse sand and fine gravel occur at the base of the formation in southwest Alabama (Meridian Sand Member).
Lithology: claystone; clay or mud; sand; sandstone; gravel
Devonian-Missisippian undivided (Devonian-Mississippian) at surface, covers < 0.1 % of this area
Devonian-Missisippian undivided (DMu): Includes Fort Payne Chert, Chattanooga Shale in Dade Co.; Fort Payne Chert at top, Chattanooga Shale in middle and Armuchee Shale at bottom in all areas except Polk Co. and Dade Co.; Fort Payne Chert, and Armuchee Chert in Polk Co. CHATTANOOGA Shale (Dc)
Lithology: shale ; chert
Wilcox Group; Hatchetigbee Formation (Eocene) at surface, covers 0.6 % of this area
Hatchetigbee Formation - (Wilcox Group), Light to dark-gray laminated carbonaceous clay, silt and very fine to fine sand, and cross-bedded glauconitic sand; one or more thin beds of fossiliferous marly glauconitic sand and sandstone occur in the upper part. Near the base is a prominent bed of glauconitic calcareous sand containing abundant fossils and spheroidal to pillow-shaped sandstone concretions (Bashi Marl Member). In parts of southeast AL the upper beds of the Th were either eroded or not deposited and the overlying Tt formation directly overlies the Bashi Marl Member.
Lithology: clay or mud; sand; silt; sandstone
Fort Payne Chert (Mississippian) at surface, covers 2 % of this area
Fort Payne Chert - Very light to light-olive-gray, thin to thick-bedded fine to coarse-grained bioclastic (abundant pelmatozoans) limestone containing abundant nodules, lenses and beds of light to dark-grey chert. Upper part of formation locally consists of light-bluish-gray laminated siltstone containing vugs lined or filled with quartz and scattered throughout the formation are interbeds of medium to greenish-gray shale, shaly limestone and siltstone. Commonly present below the Fort Payne is a light-olive-gray claystone or shale (Maury Formation) which is mapped with the Fort Payne. The apparent thickness of the Fort Payne in this province varies due to differnetial dissolution of carbonate in the formation.
Lithology: limestone; chert; siltstone; shale; claystone
Wilcox Group; Nanafalia Formation (Paleocene) at surface, covers 2 % of this area
Nanafalia Formation - (Wilcox Group), Members of the Nanafalia Formation follow in descending order. Grampian Hills Member - medium-gray massive clay, claystone, sandy fossiliferous clay, and fossiliferous fine sand. "Ostrea thirsae beds" - glauconitic, abundantly fossiliferous, quartzose fine to medium sand. Gravel Creek Sand Member - pale-yellowish-orange to moderate-reddish-brown micaceous cross-bedded fine to very coarse sand containing gravel and clay pebbles in some exposures. Gravel Creek Member is absent locally and near the base may contain thin beds of lignite. Updip deposits in northern Henry County and southern Barbour County include beds of alternating medium-gray and white clay, carbonaceous clay, white and grayish-yellow fine to coarse sand and lenses of bauxite and bauxitic clay. Sand beds commonly are cross-bedded, gravelly, and contain numerous clay pebbles. The sequence of beds is often obscured by weathering and the collapse of beds into sinkholes in the underlying Clayton Formation.
Lithology: clay or mud; claystone; sand; gravel; coal
Poe Bridge Mountain Group; Garnet quartzite (garnetite) and garnitiferous altered mafic rock (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Poe Bridge Mountain Group; Garnet quartzite (garnetite) and garnitiferous altered mafic rock. Rocks in the area of Turkey Heaven Mountain in Cleburne and Randolph Counties that are here assigned to the Poe Bridge Mountain Group also have been interpreted as part of the Wedowee Group.
Lithology: quartzite; mafic metavolcanic rock
Eutaw Formation (Cretaceous) at surface, covers 3 % of this area
Eutaw Formation - Light-greenish-gray to yellowish-gray cross-bedded, well-sorted, micaceous, fine to medium quartz sand that is fossiliferous and glauconitic in part and contains beds of greenish-gray micaceous, silty clay and medium-dark-gray carbonaceous clay. Light-gray glauconitic fossiliferous sand, thin beds of sandstone, and massive accumulations of fossil oyster shells occur locally in the upper part of the formation in western AL (Tombigbee Sand Member). In eastern AL thin to thick-bedded accumulations of the fossil oyster Ostrea cretacea Morton occur throughout much of the formation.
Lithology: sand; clay or mud; sandstone;
Kahatchee Mountain Group; Wash Creek Slate (Precambrian?-Cambrian?) at surface, covers 0.1 % of this area
Wash Creek Slate - grayish-green to black micaceous, partly carbonaceous to graphitic slate and metasiltstone containing interbedded light-gray to light-brown fine to coarse-grained metasandstone.
Lithology: slate; metasedimentary rock
Parkwood and Pennington Formations undifferentiated (Pennsylvanian-Mississippian) at surface, covers 0.1 % of this area
Parkwood and Pennington Formations undifferentiated - Interbedded medium to dark-gray shale and light to medium-gray sandstone, locally contains lithic conglomerate, dusky-red and grayish-green mudstone, argillaceous limestone, and clayey coal.
Lithology: shale; sandstone; conglomerate; mudstone; limestone; clay or mud; mixed clastic/coal
Knox Group undifferentiated (Ordovician-Cambrian) at surface, covers 2 % of this area
Knox Group undifferentiated - Light-gray to light-brown locally sandy dolomite, dolomitic limestone, and limestone; characterized by abundant light-colored chert.
Lithology: dolostone (dolomite); limestone; chert
Hatchet Creek Group; Pinchoulee Gneiss (Precambrian to Paleozoic) at surface, covers 0.1 % of this area
Pinchoulee Gneiss - medium to fine-grained migmatitic, locally garnetiferous biotite-feldspar gneiss, commonly saturated with granitic pods.
Lithology: felsic gneiss; granite
Parkwood Formation (Pennsylvanian-Mississippian) at surface, covers 0.4 % of this area
Parkwood Formation - Interbedded medium to dark-gray shale and light to medium-gray sandstone; locally contains dusky-red and grayish-green mudstone, argillaceous limestone, and clayey coal.
Lithology: shale; sandstone; mudstone; limestone; clay or mud; mixed clastic/coal
Tuscaloosa Group; Gordo Formation (Cretaceous) at surface, covers 4 % of this area
Gordo Formation - (Tuscaloosa Group), Massive beds of cross-bedded sand, gravelly sand, and lenticular beds of locally carbonaceous partly mottled moderate-red and pale-red-purple clay; lower part is predominantly a gravelly sand consisting chiefly of chert and quartz pebbles. Not mapped east of the Tallapooza River.
Lithology: sand; clay or mud; gravel; chert
Hillabee Greenstone (Paleozoic) at surface, covers 0.1 % of this area
Hillabee Greenstone - pale-green to light-olive-brown massive, fine-grained greenstone interbedded locally with well-foliated mafic phyllite.
Lithology: greenstone; phyllite
Higgins Ferry Group (Precambrian to Paleozoic) at surface, covers 0.2 % of this area
Higgins Ferry Group - thinly layered coarse to fine-grained biotite-feldspar-quartz gneiss, sericite-feldspar-muscovite schist, +/- biotite +/- garnet-muscovite schist, and biotite-garnet feldspathic gneiss; locally common pegmatites.
Lithology: felsic gneiss; mica schist; pegmatite
Wilcox Group; Tuscahoma Sand (Paleocene) at surface, covers 3 % of this area
Tuscahoma Sand - (Wilcox Group), Light-gray to light-olive-gray laminated and thin-bedded carbonaceous silt and clay interbedded with fine sand; thin lignite beds occur locally. Lower part of the formation includes beds of fossiliferous, glauconitic fine quartz sand containing speroidal sandstone concretions, gravel and clay pebbles.
Lithology: clay or mud; silt; sand; coal; sandstone; gravel
Wedowee Group; Wedowee Group undifferentiated (Precambrian to Paleozoic) at surface, covers 1.0 % of this area
Wedowee Group undifferentiated - Wedowee Group undifferentiated includes the Cragford Phyllite and Cutnose Gneiss. Cragford Phyllite -- interbedded fine-grained graphite-chlorite-sericite schist and phyllite, garnet-sericite schist and phyllite, graphite-quartz-sericite phyllite, locally feldspathic biotite gneiss, calc-silicate rock, and quartzite. Cutnose Gneiss -- cyclically interbedded fine-grained quartz-biotite feldspathic gneiss, graphite-chlorite-sericite schist, locally thin interbeds of graphite-quartz-sericite phyllite, and quartzite. Rocks in the area northeast of Clanton in Chilton and Coosa Counties that are here assigned to the Wedowee Group also have been interpreted as part of the Higgins Ferry Group.
Lithology: schist; phyllite; felsic gneiss; quartzite; calc-silicate rock
Pottsville Formation (upper part) (Pennsylvanian) at surface, covers 4 % of this area
Pottsville Formation (upper part) - Interbedded dark-gray shale, siltstone, medium-gray sandstone, and coal in cyclic sequences. In descending order the members include: Razburg Sandstone Member, Camp Branch Sandstone Member, Lick Creek Sandstone Member, and the Bremen Sandstone Member.
Lithology: shale; siltstone; sandstone; coal
Sequatchie Formation, Colvin Mountain Sandstone, Greensport Formation undifferentiated (Ordovician) at surface, covers < 0.1 % of this area
Sequatchie Formation, Colvin Mountain Sandstone, Greensport Formation undifferentiated - variegated dusky-red and pale-yellowish-orange shale, calcareous mudstone, dolomite, siltstone, and minor sandstone. Mapped in areas of facies transition with the Chickamauga Limestone (Canoe Creek, Dunaway, and Hensley Mountains).
Lithology: shale; mudstone; dolostone (dolomite); siltstone; sandstone
Monteagle Limestone (Mississippian) at surface, covers 1.0 % of this area
Monteagle Limestone - Light-gray oolitic limestone containing interbedded argillaceous, bioclastic, or dolomitic limestone, dolomite, and medium-gray shale.
Lithology: limestone; dolostone (dolomite); shale
High terrace deposits (Pleistocene) at surface, covers 1 % of this area
High terrace deposits - Varicolored lenticular beds of poorly sorted sand, ferruginous sand, silt, clay, and gravelly sand. Sand consists primarily of very fine to very coarse poorly sorted quartz grains; gravel composed of quartz, quartzite, and chert pebbles.
Lithology: terrace
Frog Mountain (Devonian) at surface, covers < 0.1 % of this area
Frog Mountain
Lithology: sandstone
Wedowee Group; Hackneyville Schist (Precambrian to Paleozoic) at surface, covers 0.2 % of this area
Hackneyville Schist - medium to coarse-grained quartz-plagioclase +/- almandine +/- kyanite +/- biotite-muscovite schist, graphite-muscovite-quartz schist, and quartzite containing biotite. Large porphyroblasts of muscovite, andalusite and/or chiastrolite common. Rocks in the areas between Goodwater in Coosa County and Millerville in Clay County that are here assigned to the Hackneyville Schist also have been interpreted as part of the Higgins Ferry Group.
Lithology: schist; quartzite
Claiborne Group; Gosport Sand and Lisbon Formation undifferentiated in part (Eocene) at surface, covers 0.9 % of this area
Gosport Sand - (Claiborne Group), highly fossiliferous, glauconitic, quartz sand and lenses of greenish-gray clay; occurs between MS state line and AL River.
Lithology: sand; clay or mud
Talladega Group; No name on map (Silurian?-Devonian) at surface, covers < 0.1 % of this area
No name on map - fossiliferous chert facies in vicinity of Jemison, Chilton County, contains marine invertabrate fossils of early to Middle Devonian age.
Lithology: chert
Bangor Limestone (Mississippian) at surface, covers 2 % of this area
Bangor Limestone - Medium-gray bioclastic and oolitic limestone, containing interbeds of dusky-red and olive-green mudstone in the upper part.
Lithology: limestone; mudstone
Hartselle Sandstone (Mississippian) at surface, covers 0.9 % of this area
Hartselle Sandstone - Light-colored thick-bedded to massive quartzose sandstone, containing interbeds of dark-gray shale.
Lithology: sandstone; shale
Pine Mountain Group; Hollis Quartzite (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Hollis Quartzite - quartzite containing minor mica, feldspar, and pyrite; locally arkosic; commonly sheared.
Lithology: quartzite
Oligocene Series undifferentiated (Oligocene) at surface, covers 0.4 % of this area
Oligocene Series undifferentiated - Descriptions of the units of the Oligocene Series follow in descending order. Paynes Hammock Sand - locally fossiliferous, calcareous, argillaceous medium to coarse sand; pale-blue-green clay; and thin-bedded sandy limestone; exposed at Paynes Hammock and at St. Stephens. Chickasawhay Limestone - white to yellowish-gray fossiliferous, glauconitic limestone and soft marl. Byram Formation includes three members in descending order: Bucatunna Clay Member - dark, bentonitic, carbonaceous, sparsely fossiliferous clay and greyish-yellow sand; unnamed marl member - light-grey to yellowish-grey sandy, glauconitic , fossiliferous marl; Glendon Limestone Member - irregularly indurated coquinoid and crystalline limestone, weathering to indurated rock containing large tubular cavities, locally known as 'horsebone'. Marianna Limestone - white to yellowish-grey soft, porous, very fossiliferous limestone. Forest Hill sand - dark-greenish-grey carbonaceous clay with lenses of glauconitic fossiliferous sand; extends eastward from MS into Choctaw, Clarke and Washington Counties. Red Bluff Clay - greenish-gray calcareous clay locally containing selenite crystals, yellowish-grey glauconitic, fossiliferous limestone; and light-gray silty clay with interbeds of sand (Forest Hill equivalent); from Tombigbee River eastward grades into glauconitic fossiliferous limestone equivalent to the Bumpnose Limestone. Bumpnose Limestone - very light-gray to yellowish-gray chalky, subcoquinoid, glauconitic, argillaceous, fossiliferous limestone; intertongues with Red Bluff Clay in vicinity of the Alabama River and is readily differentiated eastward from the Sepulga River.
Lithology: limestone; clay or mud; sand; bentonite
Claiborne Group; Gosport Sand and Lisbon Formation undifferentiated in part (Eocene) at surface, covers 2 % of this area
Lisbon Formation undifferentiated in part - (Claiborne Group), greenish-gray calcareous, glauconitic, fossiliferous clayey sand; marl; carbonaceous sand; carbonaceous silty clay; and coarse glauconitic, fossiliferous, quartz sand.
Lithology: sand; clay or mud;
Kowaliga Gneiss (Precambrian to Paleozoic) at surface, covers 0.2 % of this area
Kowaliga Gneiss - coarse-grained granodiorite to quartz monzonite with large plagioclase augen; generally shared among margins.
Lithology: granodiorite; quartz monzonite
Chickamauga Limestone (Ordovician) at surface, covers 0.2 % of this area
Chickamauga Limestone - Medium to dark-gray thick to thin-bedded partly argillaceous, locally fossiliferous limestone. Restricted to the western part of the Valley and Ridge province and Murphrees Valley and Wills Valley anticlines. Locally includes a thin interval of Attalla Chert Conglomerate Member at base. Attalla Chert Conglomerate - conglomerate of pebbles, cobbles, and boulders of chert and rare dolomite and quartzite in a sand-sized matrix; thin beds of gray-green or dusky-red shale common at base.
Lithology: limestone; conglomerate; chert; shale; dolostone (dolomite); quartzite
Pottsville Formation (Pennsylvanian) at surface, covers 3 % of this area
Pottsville Formation - Light-gray thin to thick-bedded quartzose sandstone and conglomerate containing interbedded dark-gray shale, siltstone, and coal. Mapped on Lookout Mountain, Blount and Chandler Mountains, and Sand Mountain northeats of Blount County, and on the mountains of Jackson, Marshall and Madison Counties north and west of the TN river.
Lithology: sandstone; conglomerate; shale; siltstone; coal
Parkwood Formation and Floyd Shale undifferentiated (Pennsylvanian-Mississippian) at surface, covers 0.8 % of this area
Parkwood Formation and Floyd Shale undifferentiated - Parkwood Formation -- Interbedded medium to dark-gray shale and light to medium-gray sandstone; locally contains dusky-red and grayish-green mudstone, argillaceous limestone, and clayey coal. Floyd Shale -- Dark-gray shale, sideritic in part; thin beds of sandstone, limestone and chert are locally present; beds of partly bioclastic, partly argillaceous limestone are abundant in parts of Calhoun and Cherokee Counties.
Lithology: shale; sandstone; mudstone; limestone; chert; mixed clastic/coal; clay or mud
Zana Granite (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Zana Granite - quartz monzonite to granite with strong gneissic texture, cut by small pegmatites and aplite dikes, generally elongate; semiconcordant to foliation of country rock.
Lithology: quartz monzonite; granite; pegmatite; aplite
Tuscumbia Limestone and Fort Payne Chert undivided (Mississippian) at surface, covers 0.4 % of this area
Tuscumbia Limestone and Fort Payne Chert undivided - Tuscumbia Limestone -- light-gray partly oolitic limestone; very coarse bioclastic crinoidal limestone common; light-gray chert nodules and concretions locally abundant. Fort Payne Chert -- very light to light-olive-gray, thin to thick-bedded fine to coarse-grained bioclastic (abundant pelmatozoans) limestone containing abundant nodules, lenses and beds of light to dark-grey chert. Upper part of formation locally consists of light-bluish-gray laminated siltstone containing vugs lined or filled with quartz and scattered throughout the formation are interbeds of medium to greenish-gray shale, shaly limestone and siltstone. Lenses of dark-gray siliceous shale occur locally at the base of the Fort Payne in Wills Valley. Commonly present below the Fort Payne is a ligh-olive-gray claystone or shale (Maury Formation) which is mapped with the Fort Payne. The Tuscumbia and Fort Payne are undifferentiated in Murphrees and Wills Valleys.
Lithology: limestone; chert; siltstone; shale; claystone
Ordovician [units] including Richmond Group (which includes Mannie Shale, Fernvale Limestone, Sequatchie Formation, and Arnheim Formation), the Maysville Group (which includes Leipers Formation), the Eden Group (which includes Inman Formation), and the Nashville Group (which includes Catheys Formation) (Ordovician) at surface, covers < 0.1 % of this area
Ordovician [units] including Richmond Group (which includes Mannie Shale - Olive-gray shale. Thickness 0 to 20 feet; Fernvale Limestone - Massive, coarsely crystalline, gray limestone with varicolored grains. Thickness 0 to 50 feet; Sequatchie Formation - Olive-gray and greenish-gray shale, mudstone, and argillaceous limestone; dolomitic, laminated, and sandy. Thickness 0 to 100 feet; and Arnheim Formation Nodular, shaly, gray limestone. Thickness 0 to 20 feet; the Maysville Group (which includes Leipers Formation - Nodular, shaly limestone; fine- to coarse-grained limestone; and phosphatic calcarenite locally. Thickness 0 to 150 feet); the Eden Group (which includes the Inman Formation - Thin-bedded to laminated, fine-grained, gray limestone with shale partings. Thickness 0 to 50 feet); and the Nashville Group (which includes Catheys Formation - Nodular, shaly limestone; fine- to coarse-grained limestone; phosphatic calcarenite; and light-gray cryptograined limestone. Thickness 50 to 175 feet.)
Lithology: shale ; limestone
Conasauga Formation (Cambrian) at surface, covers 1 % of this area
Conasauga Formation - Medium-bluish-gray fine-grained, thin-bedded argillaceous limestone and interbedded dark-gray shale in varying proportions.
Lithology: limestone; shale
Bibb Dolomite (Cambrian) at surface, covers < 0.1 % of this area
Bibb Dolomite - dark-gray thick-bedded siliceous dolomite; characterized by locally abundant chert containing irregular cavities.
Lithology: dolostone (dolomite); chert
Newala Limestone (Ordovician) at surface, covers < 0.1 % of this area
Newala Limestone
Lithology: limestone
Stones River Group; Carters Limestone (Ordovician) at surface, covers < 0.1 % of this area
Stones River Group; Carters Limestone - Fine-grained, yellowish-brown limestone; thin-bedded in upper part; thicker bedded and very slightly cherty with scattered mottlings of magnesian limestone in lower part. Contains thin bentonite beds. Thickness 50 to 100 feet.
Lithology: limestone; bentonite
Sylacauga Marble Group; Fayetteville Phyllite (Cambrian?-Ordovician?) at surface, covers < 0.1 % of this area
Fayetteville Phyllite - dusky-red and medium-gray phyllite and slate interlayered with light-brown to light-gray feldspathic metasiltstone, fine-grained metasandstone and dolomite marble.
Lithology: phyllite; slate; metasedimentary rock; marble
Unnamed (upper part of Knox Group), including Newala Formation, Mascot Dolomite, Kingsport Formation, Longview Dolomite, and Chepultepec Dolomite (Ordovician) at surface, covers < 0.1 % of this area
(Onc) Unnamed (upper part of the Knox Group), including the (On) Newala Formation; (Oma) Mascot Dolomite - Light-gray, fine-grained, well-bedded cherty dolomite; mottled (red and green) dolomite characteristic; interbeds of bluish-gray limestone in upper part; chert-matrix quartz sandstone at base. Erosional unconformity at top. Thickness 350 to 800 feet; (Ok) Kingsport Formation - Gray, fine-grained, sparingly cherty dolomite with basal dense, gray limestone sequence. Thickness about 250 feet. and (Olc) Unnamed (middle part of the Knox Group), including (Olv) Longview Dolomite - Siliceous, gray, fine-grained, medium-bedded dolomite; interbeds of gray limestone in upper part. Thickness about 300 feet; (Oc) Chepultepec Dolomite - Light-gray, fine-grained, well-bedded dolomite, moderately cherty; fine-grained limestone locally in upper part; quartz sandstone beds at base. Average thickness about 800 feet.
Lithology: dolostone (dolomite); limestone; sandstone
Alluvium (Pleistocene/Holocene) at surface, covers < 0.1 % of this area
Alluvium - Undifferentiated Quaternary Sediments - Much of Florida's surface is covered by a varying thickness of undifferentiated sediments consisting of siliciclastics, organics and freshwater carbonates. Where these sediments exceed 20 feet (6.1 meters) thick, they were mapped as discrete units. In an effort to subdivide the undifferentiated sediments, those sediments occurring in flood plains were mapped as alluvial and flood plain deposits (Qal). Sediments showing surficial expression of beach ridges and dunes were mapped separately (Qbd) as were the sediments composing Trail Ridge (Qtr). Terrace sands were not mapped (refer to Healy [1975] for a discussion of the terraces in Florida). The subdivisions of the Undifferentiated Quaternary Sediments (Qu) are not lithostratigraphic units but are utilized in order to facilitate a better understanding of the State's geology. The siliciclastics are light gray, tan, brown to black, unconsolidated to poorly consolidated, clean to clayey, silty, unfossiliferous, variably organic-bearing sands to blue green to olive green, poorly to moderately consolidated, sandy, silty clays. Gravel is occasionally present in the panhandle. Organics occur as plant debris, roots, disseminated organic matrix and beds of peat. Freshwater carbonates, often referred to as marls in the literature, are scattered over much of the State. In southern Florida, freshwater carbonates are nearly ubiquitous in the Everglades. These sediments are buff colored to tan, unconsolidated to poorly consolidated, fossiliferous carbonate muds. Sand, silt and clay may be present in limited quantities. These carbonates often contain organics. The dominant fossils in the freshwater carbonates are mollusks.
Lithology: alluvium; clay or mud; sand; silt; gravel; biogenic sediment; peat
Knox Group undifferentiated (Ordovician-Cambrian) at surface, covers < 0.1 % of this area
Knox Group undifferentiated
Lithology: dolostone (dolomite); limestone
Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones - mylonite and blastomylonite; contains minor ultramylonite, mylonite schist, and mylonite gneiss.
Lithology: mylonite; schist; gneiss
Pennington Formation (Mississippian) at surface, covers 0.3 % of this area
Pennington Formation - Medium-gray shale, containing interbedded limestone, dolomite, argillaceous sandstone, dusky-red and grayish-olive mudstone, and minor shaly coal. Mainly restricted to eastern part of Interior Low Plateaus province and where less than 100 feet thick the formation is included in the Bangor Limestone.
Lithology: shale; limestone; dolostone (dolomite); sandstone; mudstone; mixed clastic/coal
Selma Group; Mooreville Chalk (Cretaceous) at surface, covers 2 % of this area
Mooreville Chalk - (Selma Group), Yellowish-gray to olive-gray compact fossiliferous clayey chalk and chalky marl. The unconformable contact at the base is characterized by a bed of glauconitic, chalky sand containing phosphate pellets and molds of fossils. The Arcola Limestone Member at the top consists of two to four beds of light-gray brittle, dense, fossiliferous limestone separated by beds of light-gray to pale-olive calcareous clay.
Lithology: carbonate; mixed clastic/carbonate; sand; limestone; clay or mud
Talladega Group; Butting Ram Sandstone (Silurian?-Devonian) at surface, covers < 0.1 % of this area
Butting Ram Sandstone - white to light-bluish-gray medium to coarse-grained, locally conglomeratic thick-bedded quartzose sandstone. Possible Devonian fossils.
Lithology: sandstone; conglomerate
Miocene Series undifferentiated (Miocene) at surface, covers 6 % of this area
Miocene Series undifferentiated - Moderate-yellowish-orange thin-bedded to massive fine to coarse sand, gravelly sand, thin-bedded to massive clay and sandy clay. Clays are plastic in part. Limonite pellets occur in places along clay-sand contacts. Gravel is composed of quartz and chert granules and pebbles. Locally the upper part of the unit is Pliocene in age.
Lithology: sand; clay or mud; gravel; chert
Midway Group; Porters Creek Formation (Paleocene) at surface, covers 1 % of this area
Porters Creek Formation - (Midway Group), dark-gray massive plastic clay in western AL with a thin bed of glauconitic shell marl at the top (Mathews Landing Marl Member). Becomes calcareous eastward grading into light-greenish-gray calcareous, micaceous, clayey fine to medium sand, medium-gray sandy, calcareous clay and white to light-gray thin bedded partly clayey, fossiliferous limestone. East of Crenshaw County, owing to lithologic similarity, beds correlative with the Porters Creek are included in the Clayton Formation.
Lithology: clay or mud; sand; limestone
Shady Dolomite (Cambrian) at surface, covers 0.1 % of this area
Shady Dolomite - bluish-gray or pale-yellowish-gray thick-bedded siliceous dolomite; characterized by coarsely crystalline porous chert.
Lithology: dolostone (dolomite); chert
Selma Group; Providence Sand (Cretaceous) at surface, covers 1 % of this area
Providence Sand - (Selma Group), Upper part consists of cross-bedded fine to coarse sand and white, dark-gray and pale-red-purple mottled clay containing lignite, sand, and kaolin; lower part consists of dark-gray laminated to thin-bedded silty clay and abundantly micaceous, carbonaceous, fossiliferous very fine to fine sand. The Providence Sand extends eastward from southeastern Lowndes County into Georgia.
Lithology: sand; clay or mud; silt; coal
Stones River Group; Lebanon Limestone (Ordovician) at surface, covers < 0.1 % of this area
Stones River Group; Lebanon Limestone - Thin-bedded, gray limestone with calcareous shale partings. Thickness 80 to 100 feet.
Lithology: limestone; shale
Red Mountain Formation (Silurian) at surface, covers 0.2 % of this area
Red Mountain Formation - Interbedded yellowish-gray to moderate-red sandstone, siltstone and shale; greenish-gray to moderate-red fossiliferous partly silty and sandy limestone; few thin hematitic beds.
Lithology: sandstone; shale; siltstone; limestone
Pottsville Formation (upper part) (Pennsylvanian) at surface, covers 0.9 % of this area
Pottsville Formation (upper part) - Interbedded dark-gray shale, siltstone, medium-gray sandstone, and coal in cyclic sequences. The members present in the Cahaba synclinorium in descending order include: the Straven Conglomerate Member, Rocky Ridge Sandstone Member, and Chestnut Sandstone Member. The members present in the Coosa synclinorium in descending order include: Straight Ridge Sandstone Member and Wolf Ridge Sandstone Member.
Lithology: shale; siltstone; sandstone; coal
Citronelle Formation (Pleistocene-Pliocene) at surface, covers 3 % of this area
Citronelle Formation - moderate-reddish-brown deeply weathered fine to very coarse quartz sand and varicolored typically mottled lenticular beds of clay and clayey gravel. Limonite pebbles and lenses of limonite cemented sand occur locally in weathered exposures. Gravel is composed of chert and quartz pebbles.
Lithology: sand; clay or mud; gravel; chert
Metaclastic rocks of unknown affinity (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Metaclastic rocks of unknown affinity - in the area south of Talladega, Talladega County, the unit includes greenish-gray chlorite-sericite phyllite; in small area south of Childersburg the unit consists of greenish-gray chlorite-sericite phyllite and slate locally containing interbeds of metagraywacke; and in the area east of Columbiana, Shelby County, the unit includes dark-greenish-gray slate and metasiltstone containing interbedded coarse-grained to conglomerate quartzite.
Lithology: phyllite; slate; metasedimentary rock; quartzite
Dadeville Complex; Camp Hill Granite Gneiss (Precambrian to Paleozoic) at surface, covers 0.3 % of this area
Camp Hill Granite Gneiss - coarse to medium-grained foliated granite to quartz diorite (tonalite) gneiss, locally biotite-rich; locally contains thin amphibolite pods and lenses. Boundary between Rock Mills Granite Gneiss and Camp Hill Granite Gneiss arbitrarily defined.
Lithology: granitic gneiss; amphibolite
Little Oak Limestone (Ordovician) at surface, covers < 0.1 % of this area
Little Oak Limestone - dark-gray medium to thick-bedded fossiliferous, argillaceous to silty limestone containing chert nodules. Locally includes thin beds of bentonite in the upper part.
Lithology: limestone; chert; bentonite
Selma Group; Prairie Bluff Chalk (Upper Cretaceous) at surface, covers 0.3 % of this area
Prairie Bluff Chalk - (Selma Group), Very light-gray to light-bluish-gray firm sandy, fossiliferous brittle chalk and grayish-black silty sandy calcareous glauconitic, fossiliferous clay; semi-indurated beds of sandy, clayey limestone are present in some exposures. Abscent locally in parts of Marengo, Dallas and Wilcox Counties where overlapped by the Clayton Formation or eroded. The Prairie Bluff thins eastward from southwestern Lowndes County to northern Pike County where it interfingers with the Providence Sand.
Lithology: carbonate; clay or mud; sand; silt; limestone
Weisner and Wilson Ridge Formations undifferentiated (Cambrian) at surface, covers 0.1 % of this area
Weisner and Wilson Ridge Formations undifferentiated -- interbedded quartzose to slightly feldspathic sandstone and laterally continous conglomerate in ledge-forming units separated by greenish-gray silty mudstone.
Lithology: sandstone; conglomerate; mudstone
Newala Limestone (Ordovician) at surface, covers 0.2 % of this area
Newala Limestone - light to dark-gray thick-bedded micritic and peloidal limestone and minor dolomite.
Lithology: limestone; dolostone (dolomite)
Pine Mountain Group; Manchester Schist (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Manchester Schist - interlayered muscovite-quartz schist and quartzite, locally contains garnet, sillimanite and graphite; commonly intensely shared.
Lithology: schist; quartzite
Mississippian undifferentiated (Mississippian) at surface, covers < 0.1 % of this area
Mississippian undifferentiated: Includes Pennington Shale, Bangor Limestone (except in Floyd County), Hartselle Sandstone, Golconda Formation, Gasper Limestone, Ste. Genevieve Limestone and St. Louis Limestone
Lithology: limestone; shale; sandstone
Selma Group; Ripley Formation (Cretaceous) at surface, covers 2 % of this area
Ripley Formation - (Selma Group), Light-gray to pale-olive massive, micaceous, glauconitic, fossiliferous fine sand; sandy calcareous clay; and thin indurated beds of fossiliferous sandstone.
Lithology: sand; clay or mud; sandstone
Ketona Dolomite (Cambrian) at surface, covers 0.1 % of this area
Ketona Dolomite - Light to medium-gray thick-bedded coarsely crystalline dolomite.
Lithology: dolostone (dolomite)
Pottsville Formation (lower part) (Pennsylvanian) at surface, covers 0.3 % of this area
Pottsville Formation (lower part) - Light-gray thick-bedded to massive pebbly quartzose sandstone, containing varying amounts of interbedded dark-gray shale, siltstone, and thin discontinuos coal. In both the Cahaba and Coosa synclinoria the members in descending order include: the Pine Sandstone Member and the Shades Sandstone Member. Top of unit is mapped at top of Pine Sandstone Member.
Lithology: sandstone; shale; siltstone; coal
Talladega Group; Jemison Chert and Chulafinnee Schist undifferentiated (Silurian?-Devonian) at surface, covers 0.1 % of this area
Jemison Chert and Chulafinnee Schist undifferentiated - grayish-white to yellowish-orange massive, thick-bedded, fine-grained, locally argillaceous, locally fossiliferous metachert and light to dark-greenish-gray fine to medium-grained fissile quartz-sericite-chlorite phyllite and schist which locally includes thin chlorite phyllite and quartzose phyllite beds.
Lithology: schist; phyllite; metasedimentary rock
Floyd Shale (Mississippian) at surface, covers 0.3 % of this area
Floyd Shale - Dark-gray shale, sideritic in part; thin beds of sandstone, limestone and chert are locally present; beds of partly bioclastic, partly argillaceous limestone are abundant in parts of Calhoun and Cherokee Counties.
Lithology: shale; sandstone; limestone; chert
Opelika Complex; Auburn Gneiss, Unnamed unit (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Opelika Complex; Auburn Gneiss, Unnamed unit - unnamed unit comprised of masses of medium- to coarse-grained muscovite-biotite schist, locally garnetiferous; grades into oa.
Lithology: mica schist
Tuscaloosa Formation (Cretaceous) at surface, covers < 0.1 % of this area
Tuscaloosa Formation - Poorly sorted, light-gray chert gravel in a matrix of silt and sand; locally interbedded with sand and clay lenses. Thickness 0 to 140 feet.
Lithology: gravel; silt; sand; clay or mud
Stones River Groups undifferentiated in part (Ordovician) at surface, covers < 0.1 % of this area
Stones River Groups undifferentiated in part - medium to dark-gray thick to thin-bedded limestone, argillaceous in part, locally very fossiliferous. Contains a zone of bentonite and bentonitic shale near the top. Mapped seperately from the Nashville Group only in Jackson County.
Lithology: limestone; bentonite; shale
Chattanooga Shale (Devonian) at surface, covers < 0.1 % of this area
Chattanooga Shale - Brownish-black organic shale containing light to dark-gray sandstone and rare limestone interbeds near the base.
Lithology: shale; sandstone; limestone
Ocala Limestone (Eocene) at surface, covers < 0.1 % of this area
Ocala Limestone - Dall and Harris (1892) referred to the limestones exposed near Ocala, Marion County, in central peninsular Florida as the Ocala Limestone. Puri (1953, 1957) elevated the Ocala Limestone to group status recognizing its component formations on the basis of foraminiferal faunas (biozones). Scott (1991) reduced the Ocala Group to formational status in accordance with the North American Stratigraphic Code (North American Commission on Stratigraphic Nomenclature, 1983). The Ocala Limestone consists of nearly pure limestones and occasional dolostones. It can be subdivided into lower and upper facies on the basis of lithology. The lower member is composed of a white to cream-colored, fine to medium grained, poorly to moderately indurated, very fossiliferous limestone (grainstone and packstone). The lower facies may not be present throughout the areal extent of the Ocala Limestone and may be partially to completely dolomitized in some regions (Miller, 1986). The upper facies is a white, poorly to well indurated, poorly sorted, very fossiliferous limestone (grainstone, packstone and wackestone). Silicified limestone (chert) is common in the upper facies. Fossils present in the Ocala Limestone include abundant large and smaller foraminifers, echinoids, bryozoans and mollusks. The large foraminifera Lepidocyclina sp. is abundant in the upper facies and extremely limited in the lower facies. The presence of these large foraminifers in the upper facies is quite distinctive. The Ocala Limestone is at or near the surface within the Ocala Karst District in the westcentral to northwestern peninsula and within the Dougherty Plain District in the north-central panhandle (Scott, in preparation). In these areas, the Ocala Limestone exhibits extensive karstification. These karst features often have tens of feet (meters) of relief, dramatically influencing the topography of the Ocala Karst District and the Dougherty Plain District (Scott, in preparation). Numerous disappearing streams and springs occur within these areas. The permeable, highly transmissive carbonates of the Ocala Limestone form an important part of the FAS. It is one of the most permeable rock units in the FAS (Miller, 1986).
Lithology: limestone; dolostone (dolomite)
Longview Limestone (Ordovician) at surface, covers < 0.1 % of this area
Longview Limestone - light to medium-gray thick-bedded cherty limestone and dolomite, locally sandy.
Lithology: limestone; dolostone (dolomite)
Paleozoic shale undifferentiated (Mississippian) at surface, covers < 0.1 % of this area
Paleozoic shale undifferentiated - Dark-gray shale and mudstone, locally containing thin interbeds and lenses of dark-greenish-gray sandstone includes probable Floyd Shale in area east of Gadsden, Etowah County.
Lithology: shale; mudstone; sandstone
Colvin Mountain Sandstone (Ordovician) at surface, covers < 0.1 % of this area
Colvin Mountain Sandstone - light-gray quartzose sandstone, pebbly in part. Locally contains thin beds of bentonite in the upper part.
Lithology: sandstone; bentonite
Greensport Formation (Ordovician) at surface, covers < 0.1 % of this area
Greensport Formation - variegated dusky-red and dark-yellowish-orange shale, calcareous mudstone, limestone, siltstone, and minor sandstone.
Lithology: shale; mudstone; limestone; siltstone; sandstone
Tuscaloosa Group; Coker Formation (Cretaceous) at surface, covers 3 % of this area
Coker Formation - (Tuscaloosa Group), Light-colored micaceous very fine to medium sand, cross-bedded sand, varicolored micaceous clay, and a few thin gravel beds containing quartz and chert pebbles. Beds of thinly laminated finely glauconitic very fine to fine sand, silt and dark-gray carbonaceous clay (Eoline Member) occur locally in the lower part in western AL. Locally quartz and chert gravels at the base of the formation range in size from very fine pebbles to large cobbles. In southeastern Elmore County the formation includes marine sediments consisting of glauconitic, fossiliferous, quartzose fine to medium sand and medium-gray carbonaceous silty clay. Not mapped east of the Tallapoosa River.
Lithology: sand; clay or mud; silt; gravel; chert
Selma Group; Cusseta Sand Member of the Ripley Formation (Cretaceous) at surface, covers 0.5 % of this area
Cusseta Sand Member of the Ripley Formation - (Selma Group), Cross-bedded, medium to coarse sand; glauconitic, fossiliferous fine sand; and dark-gray fossiliferous, micaceous, carbonaceous clay. The member occurs at the base of the Ripley Formation and extends from Georgia westward into Montgomery County where it merges with the Demopolis Chalk.
Lithology: sand; clay or mud
Lookout Sandstone; Sewanee Sandstone (Pennsylvanian) at surface, covers < 0.1 % of this area
Lookout Sandstone; Sewanee Sandstone
Lithology: conglomerate; sandstone
Opelika Complex; Auburn Gneiss (Precambrian to Paleozoic) at surface, covers 0.2 % of this area
Auburn Gneiss - fine-grained biotite-oligoclase gneiss intermixed with coarse-grained muscovite-biotite schist; locally contains muscovite-rich pegmatite.
Lithology: felsic gneiss; mica schist; pegmatite
Hatchet Creek Group; Hanover Schist (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Hanover Schist - coarse to fine-grained feldspathic biotite-sericite-quartz-muscovite schist, commonly containing staurolite, garnet, and locally sillimanite in northeastern outcrop areas includes zones of aluminous graphite schist, hornblende quartzite, garnet quartzite, and rare amphibolite. Schist commonly retrograded to sericite-garnet-quartz schist. Numerous granitic pegmatites.
Lithology: schist; quartzite; pegmatite; amphibolite
Little Oak and Lenoir Limestones undifferentiated (Ordovician) at surface, covers < 0.1 % of this area
Little Oak and Lenoir Limestones undifferentiated - dark-gray argillaceous, fossiliferous medium to thick-bedded limestone; locally contains rare chert in upper part and an interval of fenestral mudstone in lower part (Mosheim Limestone Member of the Lenoir Limestone). Between Siluria and Pelham in Shelby County, the Little Oak and Lenoir Limestones are separated by a tongue of the Athens Shale.
Lithology: limestone; mudstone; chert
Hissop Granite (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Hissop Granite - mesocratic to leucocratic, strongly lineated granite to granodiorite.
Lithology: granite; granodiorite
Rome Formation (Cambrian) at surface, covers 0.2 % of this area
Rome Formation - variegated thinly interbedded mudstone, shale, siltstone, and sandstone; limestone and dolomite occur locally. Quartzose sandstone commonly present near top of formation.
Lithology: mudstone; shale; siltstone; sandstone; limestone; dolostone (dolomite)
Talladega Group; Lay Dam Formation, unnamed diamictite facies (Silurian?-Devonian) at surface, covers < 0.1 % of this area
Talladega Group; Lay Dam Formation, unnamed diamictite facies - Unnamed diamictite facies of Lay Day Formation in Coosa and Chilton Counties consists of cobbles and boulders of carbonate, pelitic rocks, quartzite, chert, felsic plutonic rocks, and gneiss in a metagraywacke matrix.
Lithology: conglomerate; carbonate; mudstone; quartzite; chert; plutonic rock (phaneritic); gneiss; metasedimentary rock
Claiborne/Jackson Group; Residuum (Eocene-Oligocene) at surface, covers 4 % of this area
Residuum - (Claiborne/Jackson Group), White to moderate-reddish-orange locally mottled sandy clay and residual clay with scattered layers of gravelly medium to coarse sand, fossiliferous chert and limestone boulders and limonitic sand masses. Derived from solution and collapse of limestone in the Jackson Group and Oligocene Series and the slumping of Pliocene and Miocene sediments.
Lithology: clay or mud; residuum; sand; limestone; chert
Uchee Complex; Phenix City Gneiss (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Phenix City Gneiss - biotite-epidote quartz diorite gneiss and biotite-hornblende gneiss; locally includes migmatitic amphibolite; cut by numerous granitic veins.
Lithology: felsic gneiss; mafic gneiss; amphibolite; granite
Leipers Limestone (Ordovician) at surface, covers < 0.1 % of this area
Leipers Limestone - Leipers Limestone -- medium to dark-gray thin to medium-bedded fossiliferous limestone containing interbeds of thin argillaceous limestone. Mapped in Sequatchie Valley. Inman Formation -- interbedded greenish-gray or moderate to dusky-red shale and light-gray peloidal limestone. Mapped in Sequatchie Valley.
Lithology: limestone
Athens Shale and Lenoir Limestone undifferentiated (Ordovician) at surface, covers < 0.1 % of this area
Athens Shale and Lenoir Limestone undifferentiated - Athens Shale -- black graptolitic shale, locally contains interbedded dark-gray limestone. Lenoir Limestone -- dark-gray medium to thick-bedded argillaceous limestone; locally contains an interval of fenestral mudstone at the base (Mosheim Limestone Member).
Lithology: shale; limestone; mudstone
Sylacauga Marble Group; Gantts Quarry Formation (Cambrian?-Ordovician?) at surface, covers < 0.1 % of this area
Gantts Quarry Formation - white and pale-blue to light-gray calcite marble locally containing interlayered dolomite marble and thin phyllite layers.
Lithology: marble; phyllite
Citronelle Formation (Pliocene) at surface, covers < 0.1 % of this area
Citronelle Formation - The Citronelle Formation is widespread in the Gulf Coastal Plain. The type section for the Citronelle Formation, named by Matson (1916), is near Citronelle, Alabama. The Citronelle Formation grades laterally, through a broad facies transition, into the Miccosukee Formation of the eastern Florida panhandle. Coe (1979) investigated the Citronelle Formation in portions of the western Florida panhandle. The Citronelle Formation is a siliciclastic, deltaic deposit that is lithologically similar to, and time equivalent with, the Cypresshead Formation and, at least in part, the Long Key Formation (Cunningham et al., 1998) of the peninsula. In the western panhandle, some of the sediments mapped as Citronelle Formation may be reworked Citronelle. The lithologies are the same and there are few fossils present to document a possible younger age. The Citronelle Formation consists of gray to orange, often mottled, unconsolidated to poorly consolidated, very fine to very coarse, poorly sorted, clean to clayey sands. It contains significant amounts of clay, silt and gravel which may occur as beds and lenses and may vary considerably over short distances. Limonite nodules and limonite-cemented beds are common. Marine fossils are rare but fossil pollen, plant remains and occasional vertebrates are found. Much of the Citronelle Formation is highly permeable. It forms the Sand and Gravel Aquifer of the surficial aquifer system.
Lithology: delta; sand; clay or mud; silt; gravel
Pottsville Formation (lower part) (Pennsylvanian) at surface, covers 5 % of this area
Pottsville Formation (lower part) - Light-gray thick-bedded to massive pebbly quartzose sandstone, containing varying amounts of interbedded dark-gray shale, siltstone, and thin discontinuos coal. The Boyles Sandstone Member is a formally named unit in the lower part of the formation. Top of unit is mapped at the Black Creek coal.
Lithology: sandstone; shale; siltstone; coal
Jackson Group undifferentiated (Eocene) at surface, covers 0.8 % of this area
Jackson Group undifferentiated - The units of the Jackson Group are the Yazoo Clay and Crystal River and Moodys Branch Formations. Descriptions of the members of the Yazoo Clay follow in decending order. Shubuta Member - in western Alabama consists of light-greenish-gray to white plastic fossiliferous, calcareous clay containing irregular calcareous nodules. From the Tombigbee River eastward the Shubuta becomes more calcareous and grades into massive clayey glauconitic limestone. Eastward from the Alabama River , equivalent beds grade into the Crystal River Formation. Pachuta Marl Member - light-greenish-grey glauconitic, fossiliferous clayey sand and sandy limestone traceable from western Alabama eastward to Covington County where it grades into the Crystal River Formation. Cocoa Sand Member - yellowish-gray firm calcareous, fossiliferous fine to medium sand or sandy limestone or greenish-grey micaceous, calcareous, very clayey sand. Calcareous and clayey sand equivalent to the Cocoa is traceable from western Alabama to the Conecuh River area. North Twistwood Creek Clay Member - greenish-gray plastic calcareous, sparsely fossiliferous, blocky massive clay; grades into Crystal River formation in southeast AL. Crystal River Formation - white to yellowish-grey medium-grained to coquinoid limestone that is soft and chalky to compact and brittle; principally in southeastern AL but interfingers westward with members of the Yazoo Clay. Moodys Branch Formation - greenish-gray to pale-yellowish-orange glauconitic, calcareous, fossiliferous sand and sandy limestone; underlies the Yazoo Clay and the Crystal River Formation.
Lithology: clay or mud; limestone; sand
Tuscaloosa Group undifferentiated (Cretaceous) at surface, covers 0.8 % of this area
Tuscaloosa Group undifferentiated - Light-gray to moderate-reddish-orange clayey, gravelly fine to very coarse sand; massive mottled sandy clay; local wood and leaf beds; and thin beds of indurated sandstone. Gravel consists mainly of quartz and quartzite and range in size from very fine pebbles to large cobbles. Mapped eats of the Tallapoosa River.
Lithology: sand; clay or mud; sandstone; gravel; quartzite
Rockford Granite (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Rockford Granite - leucocratic granite, granodiorite, and trondhjemite; locally well foliated, numerous pegmatites. Includes unnamed granitoids in Chilton County.
Lithology: granite; granodiorite; trondhjemite; pegmatite
Wilcox Group; Salt Mountain Limestone (Paleocene) at surface, covers < 0.1 % of this area
Salt Mountain Limestone - (Wilcox Group), White massive, indurated fossiliferous limestone containing lenses and irregular beds of soft, friable limestone. Exposed only at Salt Mountain, on the upthrow side of the Jackson fault 5 miles south of Jackson, Clarke County.
Lithology: limestone
Heflin Phyllite (Cambrian?) at surface, covers 0.3 % of this area
Heflin Phyllite - grayish-green, medium-gray, and medium-bluish-gray calcareous sandy metasiltstone interbedded with minor greenish-gray fine to coarse-grained metasandstone and rare thin lenses of calcite and dolomite marble; an interval of greenish-gray to dark-gray phyllitic quartzite or quartz-pebble metaconglomerate is locally present near the base. The Heflin underlies the Lay Dam Formation and overlies the rocks tentatively identified as the Chilhowee Group undifferentiated.
Lithology: metasedimentary rock; quartzite; marble
Talladega Group; Cheaha Quartzite Member of Lay Dam Formation (Silurian?-Devonian) at surface, covers < 0.1 % of this area
Cheaha Quartzite Member of Lay Dam Formation - white to light-gray medium to coarse-grained arkosic quartzite and metaconglomerate.
Lithology: quartzite; meta-conglomerate
Talladega Group; Lay Dam Formation (Silurian?-Devonian) at surface, covers 1 % of this area
Lay Dam Formation (Talladega Group) - interbedded dark-green phyllite, medium-gray to light-brown and black metasiltstone, dark-green feldspathic metagraywacke, and light-gray and dark-gray medium to coarse-grained arkosic quartzite and metaconglomerate; graphitic phyllite common in upper part. In Cleburne and Calhoun Counties, rocks mapped as the Lay Dam include the Abel Gap Formation of Bearce (1973) and consist of interbedded greenish-gray metasiltstone and quartzite, black phyllitic metasiltstone, medium-gray to greenish-gray arkosic quartzite, and dark-gray pyritic quartzite. In Clay Chounty the upper part of the Lay Dam includes black graphitic sericite phyllite and slate reportedly containing plant fossils (Erin Slate Member).
Lithology: phyllite; metasedimentary rock; quartzite; slate; meta-conglomerate
Conasauga Formation, lower unnamed shale facies (Cambrian) at surface, covers < 0.1 % of this area
Conasauga Formation, lower unnamed shale facies - lower unnamed shale facies in eastern Valley and Ridge consists of dark-green to pale-olive fossiliferous shale with a few dark-gray limestone interbeds.
Lithology: shale; limestone
Talladega Group; Miller Mill Quartzite Member of the Lay Dam Formation (Silurian?-Devonian) at surface, covers < 0.1 % of this area
Miller Mill Quartzite Member of the Lay Dam Formation - white to medium-gray medium to coarse-grained arkosic quartzite and metaconglomerate.
Lithology: quartzite; meta-conglomerate
Nashville and Stones River Groups undifferentiated (Ordovician) at surface, covers < 0.1 % of this area
Nashville and Stones River Groups undifferentiated - medium to dark-gray fossiliferous limestone, argillaceous in part; yellowish-gray laminated silty limestone in upper part. Contains one or more thin beds of bentonite and bentonitic shale.
Lithology: limestone; bentonite; shale
Athens Shale (Ordovician) at surface, covers < 0.1 % of this area
Athens Shale - black graptolitic shale, locally contains interbedded dark-gray limestone.
Lithology: black shale; limestone
Mitchell Dam Amphibolite (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Mitchell Dam Amphibolite - dark-green to black fine to coarse-grained, thin-layered to massive hornblende-actinolite amphibolite; includes all amphibolite associated with the Higgins Ferry and Hatchet Creek Groups.
Lithology: amphibolite
Phyllite and Quartzite (Precambrian-Paleozoic) at surface, covers < 0.1 % of this area
Phyllite and Quartzite
Lithology: phyllite; quartzite
Pennington Formation (Mississippian) at surface, covers < 0.1 % of this area
Pennington Formation - Highly variegated clay shale, distinctive; contains siltstone and locally gray, fine-grained sandstone. Thickness 400 to 700 feet.
Lithology: shale; siltstone; sandstone
Kahatchee Mountain Group; Kalona Quartzite Member of Wash Creek Slate (Precambrian?-Cambrian?) at surface, covers < 0.1 % of this area
Kalona Quartzite Member of Wash Creek Slate - light-brown to light-gray coarse-grained, feldspathic quartzite and metaconglomerate in lower part of Wash Creek Slate.
Lithology: quartzite; meta-conglomerate
Motts Gneiss, Unnamed unit (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Motts Gneiss, Unnamed unit - unnamed unit comprised of masses of epidote-hornblende-oligoclase mylonitic gneiss and amphibolite.
Lithology: gneiss; amphibolite
Dadeville Complex; Ropes Creek Amphibolite (Precambrian to Paleozoic) at surface, covers 0.5 % of this area
Ropes Creek Amphibolite - layered and massive amphibolite; locally includes hornblende migmatite and ultramafic pods.
Lithology: amphibolite; migmatite; ultramafic intrusive rock
Higgins Ferry Group; Roscoelite-graphite-quartz schist and graphitic quartzite (Precambrian to Paleozoic) at surface, covers 0.2 % of this area
Higgins Ferry Group; Roscoelite-graphite-quartz schist and graphitic quartzite
Lithology: schist; quartzite
Midway Group; Clayton Formation (Paleocene) at surface, covers 1 % of this area
Clayton Formation - (Midway Group), White to yellowsih-gray argillaceous limestone occurs in the upper part (McBryde Limestone Member): the lower part is medium-gray fossiliferous calcareous silt, glauconitic sand and thin beds of sandy limestone and calcareous sandstone (Pine Barren Member). At the base of the formation in southeast AL is a gravelly medium to coarse sand containing clay pebbles. The formation thins west of Wilcox County and westward from Thomaston in eastern Marengo County is mapped with the Porters Creek Formation. The formation is generally deeply weathered and fresh exposures are rare. In western areas exposures consist of weathered white to yellowish-gray argillaceous, fossiliferous sandy limestone, ferruginous sand, and fossiliferous sandstone. In eastern areas exposures consist of residual accumulations of chert boulders, moderate-reddish-orange sand, and clay containing masses and thin layers of iron minerals (limonite-goethite).
Lithology: limestone; clay or mud; silt; sandstone; chert
Emuckfaw Group; Glenloch Schist (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Glenloch Schist - graphite-garnet-muscovite schist with interlayered metagraywacke.
Lithology: mica schist; metasedimentary rock
Frog Mountain Sandstone (Devonian) at surface, covers < 0.1 % of this area
Frog Mountain Sandstone -- light to dark-gray sandstone with thin dark-gray shale interbeds, light-gray to black dolomudstone, glauconitic limestone, and fossiliferous chert locally in lower part.
Lithology: sandstone; shale; mudstone; limestone; chert
Chilhowee Group undifferentiated (Cambrian) at surface, covers 0.2 % of this area
Chilhowee Group undifferentiated - light to medium-gray arkose, arkosic conglomerate, and discontinous mudstone overlain by greenish-gray mudstone with minor siltstone and sandstone; dominantly light-gray pebbly quartzose sandstone in upper part.
Lithology: conglomerate; mudstone; siltstone; sandstone
Ultramafic rock (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Ultramafic rock - ultramafic pods and sheets, principally enstatite-hypersthene pyroxenite with hornblende and actinolite alteration assemblages.
Lithology: pyroxenite
Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones (Precambrian to Paleozoic) at surface, covers 0.1 % of this area
Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones - blastomylonite, mylonite gneiss, locally includes mylonite schist and mylonite quartzite in Towaliga fault zone.
Lithology: mylonite; gneiss; schist; quartzite
Wacoochee Complex; Whatley Mill Gneiss (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Whatley Mill Gneiss - variably mylonitized coarse-grained biotite-muscovite-oligoclase gneiss with large potassium feldspar augen.
Lithology: augen gneiss
Pine Mountain Group; Chewacla Marble (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Chewacla Marble - light-gray coarse to fine-grained dolomite marble; locally rich in phlogopite.
Lithology: marble
Ordovician System undivided in part (Includes Sequatchie Formation, Elkmont Formation, Leipers Limestone, Inman Formation, Nashville Group, and Stones River Group) (Ordovician) at surface, covers 0.1 % of this area
Ordovician System undivided in part (Includes Sequatchie Formation, Elkmont Formation, Leipers Limestone, Inman Formation, Nashville Group, and Stones River Group) - Sequatchie Formation -- grayish-red and yellowish-gray calcareous shale containing interbedded fossiliferous limestone. Elkmont Formation -- medium to dark-gray phosphatic limestone with interbeds of light to medium-gray and black shale. Leipers Limestone -- medium to dark-gray thin to medium-bedded fossiliferous limestone containing interbeds of argillaceous limestone. Inman Formation -- interbedded greenish-gray or moderate to dusky-red shale and light-gray peloidal limestone. Nashville Group undifferentiated -- medium to dark-gray argillaceous and fossiliferous limestone overlain by yellowish-gray laminated silty limestone. Stones River Group -- medium to dark-gray thick to thin-bedded limestone, argillaceous in part, locally very fossiliferous.
Lithology: limestone; shale
Wedowee Group; Cornhouse Schist (Precambrian to Paleozoic) at surface, covers 0.1 % of this area
Cornhouse Schist - medium to coarse-grained multiply foliated +/- plagioclase +/- garnet-biotite-muscovite-quartz schist interlayed with chlorite-biotite-garnet schist, typically mylonitic.
Lithology: schist
Midway Group; Naheola Formation (Paleocene) at surface, covers 0.6 % of this area
Naheola Formation - (Midway Group), The Naheola Formation is restricted to western AL and pinches out in western Butler County. Descriptions of the members of the formation follow in descending order. Coal Bluff Marl Member - glauconitic sand, thin-bedded silty clay, and sandy fossiliferous marl; Oak Hill Member - laminated silt, clay, and fine sand; contains a prominent bed of lignite near the top. The Coal Bluff Marl Member in Sumter County and in parts of Marengo County is mostly cross-bedded fine to coarse sand that is indistinguishable from the overlying lower beds of the Nanafalia Formation. Therefore, in these areas, the contact between the two is mapped at the top of the Oak Hill Member of the Naheola.
Lithology: sand; clay or mud; silt; coal
Alum Bluff Group (Miocene) at surface, covers < 0.1 % of this area
Alum Bluff Group - West of the Apalachicola River, the Hawthorn Group is replaced by the Alum Bluff Group. The Alum Bluff Group includes the Chipola Formation, Oak Grove Sand, Shoal River Formation, Choctawhatchee Formation and the Jackson Bluff Formation (Huddlestun, 1984; Braunstein et al., 1988). The formations included in this group are generally defined on the basis of their molluscan faunas and stratigraphic position (Schmidt and Clark, 1980). Puri (1953) described sediment facies as they relate to the formations of the Alum Bluff Group These sediments are lithologically distinct as a group, not as individual units. Brooks (1982) mapped much of the Alum Bluff Group as the Shoal River Formation. The Alum Bluff Group crops out or is beneath a thin overburden in the western panhandle from river valleys in Okaloosa County eastward to western Jackson County. The Alum Bluff Group consists of clays, sands and shell beds which may vary from fossiliferous, sandy clays to unfossiliferous sands and clays and occasional carbonate beds (Huddlestun, 1984). Mica is a common constituent and glauconite and phosphate occur sporadically. Induration varies from essentially nonindurated in sands to well indurated in carbonate lenses. Colors range from cream to olive gray with mottled reddish brown in weathered sections. Sand grain size varies from very fine to very coarse with sporadic occurrences of gravel. These sediments generally have low permeabilities and are part of the intermediate confining unit/aquifer system.
Lithology: sandstone; claystone; limestone
Fort Payne Formation (Mississippian) at surface, covers < 0.1 % of this area
Fort Payne Formation - Bedded chert, calcareous and dolomitic, somewhat crinoidal; and minor shale. Thin green shale (Maury) at base. Average thickness about 200 feet.
Lithology: chert; shale
Devonian Formations, includes Pegram Formation, Camden Formation, Harriman Formation, Flat Gap Limestone, and Ross Formation (Devonian) at surface, covers < 0.1 % of this area
Devonian Formations - Characterized by marked north-south facies variations. Because of pre-Chattanooga and/or pre-Cretaceous warping and erosion, the distribution and thickness of Devonian formations is very irregular. Includes Pegram Formation - Thick-bedded, gray limestone and gray sandstone. Thickness 0 to 15 feet; Camden Formation - Light-gray novaculitic chert and tripolitic clay; and minor siliceous limestone. Thickness 0 to about 100 feet; Harriman Formation - Light-gray novaculitic chert and tripolitic clay; and minor siliceous limestone. (Harriman and Camden are differentiated paleontologically.) Thickness 0 to 50 feet; Flat Gap Limestone - Thick-bedded, coarse-grained limestone, gray with red and brown grains. Thickness 0 to 55 feet; Ross Formation - Siliceous limestone; gray and variegated shale; and medium-grained glauconitic limestone. Thickness 0 to 75 feet.
Lithology: limestone; chert; clay or mud; shale; sandstone
Copper Ridge Dolomite (Cambrian) at surface, covers 0.1 % of this area
Copper Ridge Dolomite - light-gray finely to coarsely crystalline, thick-bedded siliceous dolomite; characterized by abundant stromatolitic chert. Mapped seperately only in the Birmingham anticlinorium where overlying units within the Knox Group are absent beneath the post-Knox unconformity.
Lithology: dolostone (dolomite); chert
Coastal deposits (Holocene) at surface, covers < 0.1 % of this area
Coastal deposits - Loam, sand, gravel and clay.
Lithology: sand; gravel; clay or mud
Sylacauga Marble Group; Jumbo Dolomite (Cambrian?-Ordovician?) at surface, covers < 0.1 % of this area
Jumbo Dolomite - light to medium-gray thin to thick-bedded dolomite marble; contains intraclast-bearing dolomite, locally sandy in middle part.
Lithology: marble; dolostone (dolomite); sand
Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones - crushed schistose rock; includes sericite-graphite-rich rocks.
Lithology: mylonite; cataclasite
Sylacauga Marble Group; Gooch Branch Chert (Cambrian?-Ordovician?) at surface, covers < 0.1 % of this area
Gooch Branch Chert - light-gray to light-brown dolomite marble associated with abundant light-gray to white massive to moderately foliated metachert.
Lithology: marble; metasedimentary rock
Lookout Sandstone; Gizzard Formation (Pennsylvanian) at surface, covers < 0.1 % of this area
Lookout Sandstone; Gizzard Formation
Lithology: shale; sandstone; coal
Almond Trondhjemite (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Almond Trondhjemite - leucocratic, fine to medium-grained, locally foliated trondhjemite containing abundant muscovite and locally biotite and epidote.
Lithology: trondhjemite
Inman Formation (Ordovician) at surface, covers < 0.1 % of this area
Inman Formation - interbedded greenish-gray or moderate to dusky-red shale and light-gray peloidal limestone. Mapped in Sequatchie Valley.
Lithology: shale; limestone
Elkahatchee Quartz Diorite Gneiss (Precambrian to Paleozoic) at surface, covers 0.5 % of this area
Elkahatchee Quartz Diorite Gneiss - mesocratic to melanocratic, fine to coarse-grained, massive to strongly foliated, locally sheared quartz diorite gneiss.
Lithology: orthogneiss
Selma Group; Blufftown Formation (Cretaceous) at surface, covers 1.0 % of this area
Blufftown Formation - (Selma Group), The Blufftown extends from the Chattahoochee River Valley westward into central Russell County where it is divided into two westward-extending tongues by an eastward-extending tongue of the Mooreville Chalk. In the Chattahoochee River Valley the Blufftown is mainly glauconitic calcareous fine sand, micaceous clay and marl, fossiliferous clay, gray calcareous fossiliferous sandstone, and carbonaceous clay and silt. To the west the lower tongue of the Blufftown is gravelly sand, glauconitic sand, calcareous clay, and sandy clay and merges with the lower part of the Mooreville Chalk in southwestern Macon County. The upper tongue is mainly calcareous sandy clay and micaceous silty fine sand with thin layers of limestone and sandstone. The upper tongue merges with the Mooreville Chalk and the lower part of the Demopolis Chalk in western Bullock County.
Lithology: sand; mixed clastic/carbonate; clay or mud; silt; sandstone; limestone
Nichols Formation (Cambrian) at surface, covers < 0.1 % of this area
Nichols Formation - massive to laminated greenish-gray and black micaceous mudstone containing minor interbeds of siltstone and very fine-grained sandstone.
Lithology: mudstone; siltstone; sandstone
Monteagle Limestone (Mississippian) at surface, covers < 0.1 % of this area
Monteagle Limestone - Fragmental and oolitic limestone, light-gray; and fine-grained, brownish-gray limestone. Thickness 180 to 350 feet.
Lithology: limestone
Silurian System undivided (Includes Wayne Group and Brassfield Limestone) (Silurian) at surface, covers < 0.1 % of this area
Silurian System undivided (Includes Wayne Group and Brassfield Limestone) - Wayne Group - medium-gray, greenish-gray, and moderate-red argillaceous limestone; moderate-red and greenish-gray shale; and grayish-green fossiliferous limestone with scattered pink calcite crystals. Brassfield Limestone - greenish-gray to light-brownish-gray argillaceous, dolomitic, cherty, sandy, glauconitic limestone.
Lithology: limestone; shale; dolostone (dolomite); sand; chert
Dadeville Complex; Rock Mills Granite Gneiss (Precambrian to Paleozoic) at surface, covers 0.4 % of this area
Rock Mills Granite Gneiss - coarse to medium-grained biotite granite gneiss; locally includes thick bands of epidote and thin, small amphibolite bodies. Boundary between Rock Mills Granite Gneiss and Camp Hill Granite Gneiss arbitrarily defined.
Lithology: granitic gneiss; amphibolite
Chattanooga Shale and Frog Mountain Sandstone undifferentiated (Devonian) at surface, covers < 0.1 % of this area
Chattanooga Shale and Frog Mountain Sandstone undifferentiated (In areas mapped as Dcfm one or both units may be locally absent) - Chattanooga Shale -- Brownish-black organic shale containing light to dark-gray sandstone and rare limestone interbeds near the base. Frog Mountain Sandstone -- light to dark-gray sandstone with thin dark-gray shale interbeds, light-gray to black dolomudstone, glauconitic limestone, and fossiliferous chert locally in lower part.
Lithology: shale; sandstone; limestone; dolostone (dolomite); chert
Bangor Limestone and Hartselle Formation (Mississippian) at surface, covers < 0.1 % of this area
Bangor Limestone - Dark brownish-gray limestone, thick-bedded. Thickness 100 to 250 feet; and Hartselle Formation - Thin-bedded, fine-grained sandstone and greenish-gray shale interbedded with coarse limestone. Thickness 0 to 60 feet.
Lithology: limestone; sandstone; shale
Sylacauga Marble Group; Shelvin Rock Church Formation (Cambrian?-Ordovician?) at surface, covers < 0.1 % of this area
Shelvin Rock Church Formation - moderate-pink to light-gray calcite and locally dolomite marble.
Lithology: marble
Red Mountain Formation (Silurian) at surface, covers < 0.1 % of this area
Red Mountain Formation
Lithology: sandstone; shale
Wacoochee Complex; Halawaka Schist (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Halawaka Schist - feldspathic muscovite-biotite schist and quartz-diorite gneiss; locally contains lenses of muscovite-graphite schist and amphibolite; commonly cut by feldspathic veins and pegmatites.
Lithology: mica schist; gneiss; pegmatite
Pennsylvanian undifferentiated (Pennsylvanian) at surface, covers < 0.1 % of this area
Pennsylvanian undifferentiated
Lithology: sandstone; shale; conglomerate
Blufftown Formation (Cretaceous) at surface, covers < 0.1 % of this area
Blufftown Formation
Lithology: clay or mud; sand
Brierfield Dolomite (Cambrian) at surface, covers < 0.1 % of this area
Brierfield Dolomite - medium to dark-bluish-gray thick-bedded siliceous dolomite; characterized by locally abundant chert with irregular cavities.
Lithology: dolostone (dolomite); chert
Gizzard Group including Warren Point Sandstone and Raccoon Mountain Formation (Pennsylvanian) at surface, covers < 0.1 % of this area
Gizzard Group - Sandstone, conglomeratic sandstone, siltstone, shale, and minor coal. Thickness 100 to 200 feet. Includes Warren Point Sandstone - Gray to brown sandstone and minor conglomeratic sandstone. Thickness 60 to 160 feet; Raccoon Mountain Formation - Siltstone, sandstone, shale, and minor coal. Thickness 0 to 65 feet.
Lithology: sandstone; shale; siltstone; coal
Tuscumbia Limestone (Mississippian) at surface, covers 3 % of this area
Tuscumbia Limestone - Light-gray limestone, partly oolitic near top; fine to very coarse-grained bioclastic crinoidal limestone common; light-gray chert nodules and concretions are scattered throughout and are abundant locally. The apparent thickness of the formation in this province varies due to differential dissolution of the carbonate in the unit.
Lithology: limestone; chert
Bangor and Monteagle Limestones undivided in part (Mississippian) at surface, covers < 0.1 % of this area
Bangor and Monteagle Limestones undivided in part - Bangor Limestone -- medium-gray bioclastic and oolitic limestone, containing interbeds of dusky-red and olive-green mudstone in upper part. Monteagle Limestone -- light-gray oolitic limestone containing interbedded argillaceous, bioclastic, or dolomitic limestone, dolomite, and medium-gray shale.
Lithology: limestone; mudstone; dolostone (dolomite); shale
Emuckfaw Group; Emuckfaw Group undifferentiated in part (Precambrian to Paleozoic) at surface, covers 0.4 % of this area
Emuckfaw Group undifferentiated in part - interbedded muscovite +/- garnet-biotite schist, metagraywacke, calc-silicate rock, and quartzite; rare thin amphibolite. Includes thin layers of aluminous graphitic schist. Locally sheared to mylonite schist.
Lithology: mica schist; metasedimentary rock; quartzite; calc-silicate rock; amphibolite
Opelika Complex; Loachapoka Schist (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Loachapoka Schist - muscovite-quartz schist; locally contains biotite-garnet-muscovite schist, many layers conatin sillimanite (northeast of Mount Jefferson, Lee County); kyanite (west of Mount Jefferson); locally muscovite-rich schist and quartzite common.
Lithology: mica schist; quartzite
Hillabee Greenstone, unnamed dacite unit (Paleozoic) at surface, covers < 0.1 % of this area
Hillabee Greenstone, unnamed dacite unit - unnamed unit comprised of masses of well-foliated quartz dacite.
Lithology: dacite
Opelika Complex; Bottle Granite (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Bottle Granite - leucocratic, fine to medium-grained, well-foliated quartz monzonite to granite; locally porphyritic.
Lithology: quartz monzonite; granite
Chickamauga Group; Middle Ordovician rocks; Rockmart Slate (Middle Ordovician) at surface, covers < 0.1 % of this area
Chickamauga Group; Middle Ordovician rocks; Rockmart Slate
Lithology: slate
Jacksons Gap Group; Jacksons Gap Group undifferentiated in part (Precambrian to Paleozoic) at surface, covers 0.1 % of this area
Jacksons Gap Group undivided - principally graphitic sericite (muscovite)-quartz schist; includes sericite-quartz phyllonite; sericite phyllonite, blastomylonite, porphyroclastic blastomylonite schist, and mylonite quartzite occur principally along margins in south and form most of unit northeast of Jacksons Gap, Tallapoosa County.
Lithology: schist; phyllonite; mylonite; quartzite
Dadeville Complex; Waverly Gneiss (Precambrian to Paleozoic) at surface, covers 0.3 % of this area
Waverly Gneiss - feldspathic biotite-hornblende gneiss with thin layers of amphibolite, calc-silicate rock, garnet quartzite, and muscovite schist; locally rich in manganese.
Lithology: mafic gneiss; amphibolite; quartzite; mica schist; calc-silicate rock
Eutaw formation (Upper Cretaceous) at surface, covers < 0.1 % of this area
Eutaw formation - More or less cross-bedded and thinly laminated glauconitic sand and clay; basal part includes the McShan formation, greenish-gray, micaceous, locally very glauconitic, very fine-grained sand and thin-bedded light-gray clay, small chert gravels may be present in basal beds, not recognized in northern Tishomingo County.
Lithology: sand; clay or mud; gravels
Kahatchee Mountain Group; Waxahatchee Slate (Precambrian?-Cambrian?) at surface, covers 0.1 % of this area
Waxahatchee Slate - dark-gray to grayish-green thin-bedded, micaceous metasiltstone, slate, and fine-grained quartzite.
Lithology: metasedimentary rock; slate; quartzite
Kahatchee Mountain Group; Brewer Phyllite (Precambrian?-Cambrian?) at surface, covers < 0.1 % of this area
Brewer Phyllite - dusky-red micaceous slate and phyllite, locally containing interbedded micaceous arkosic quartzite and metasiltstone; locally at the base is interbedded calcite and dolomite marble.
Lithology: slate; phyllite; quartzite; metasedimentary rock; marble
Silurian Formations, including Decatur Limestone, Brownsport Group (Lobelville Formation, Bob Limestone, Beech River Formation), Wayne Group (Dixon Formation, Lego Formation, Waldron Shale, Laurel Limestone, Osgood Formation) and Brassfield Limestone (Silurian) at surface, covers < 0.1 % of this area
Silurian Formations - A complete section of Silurian formations is not common because of pre-Chattanooga and/or pre- Cretaceous erosion. Where preserved, Silurian formations are remarkably uniform in thickness and are characteristically light olive-gray to greenish-gray with variable reddish-brown color in some area;. Decatur Limestone - Thick-bedded, medium- to coarse-grained limestone, gray with reddish-brown grains. Thickness 0 to 70 feet; Brownsport Group which includes 1) Lobelville Formation - Shale with thin beds of limestone. Thickness 0 to 40 feet; 2) Bob Limestone - Thick-bedded, medium-grained limestone, locally oolitic. Thickness 0 to 25 feet; and 3) Beech River Formation - Shale with thin beds of limestone. Thickness 0 to 60 feet; Wayne Group which includes: 1) Dixon Formation - Green and reddish-brown argillaceous limestone, shale, and mudstone. Thickness 0 to 40 feet; 2) Lego Limestone - Even-bedded, olive-gray limestone with scattered reddish-brown grains. Thickness 0 to 30 feet; 3) Waldron Shale - Greenish-gray fossiliferous shale. Thickness 0 to 5 feet; 4) Laurel Limestone - Even-bedded, gray limestone with scattered reddish-brown grains. Thickness 0 to 30 feet; 5) Osgood Formation - Greenish- and reddish-gray shale and argillaceous limestone. Thickness 0 to 15 feet.; and Brassfield Limestone - Thin-bedded cherty limestone, locally glauconitic. Thickness 0 to 20 feet.
Lithology: limestone; shale; mudstone
Wacoochee Complex; Phelps Creek Gneiss (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Phelps Creek Gneiss - quartz monzonite to granite gneiss in dikes and sheets with wide migmatite zones at contacts.
Lithology: quartz monzonite; granitic gneiss; migmatite
Dadeville Complex; Agricola Schist (Precambrian to Paleozoic) at surface, covers 0.1 % of this area
Agricola Schist - biotiite +/- garnet +/- sillimanite-feldspar-quartz schist, interlayered with thin-bedded dark-brown hornblende amphibolite; contains pegmatite pods and veins.
Lithology: quartz-feldspar schist; amphibolite; pegmatite
Beaverdam Amphibolite (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Beaverdam Amphibolite - dark-green to dark-gray hornblende amphibolite, extensively sheared and folded, and locally retrograded to actinolite-tremolite-chlorite schist. Includes all amphibolite associated with the Wedowee Group.
Lithology: amphibolite; schist
Jacksons Gap Group; Jacksons Gap Group, Unnamed unit (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Jacksons Gap Group; Jacksons Gap Group, Unnamed unit - unnamed comprised of masses of interbedded grayish-green sericite phyllite and sericite-quartz-chlorite phyllite.
Lithology: phyllite
Kahatchee Mountain Group; Stumps Creek Formation (Precambrian?-Cambrian?) at surface, covers < 0.1 % of this area
Stumps Creek Formation - grayish-green micaceous metasiltstone and minor phyllite; grayish-green fine to medium-grained pyritic metasandstone in middle to upper part.
Lithology: phyllite; metasedimentary rock
Nashville Group (Ordovician) at surface, covers < 0.1 % of this area
Nashville Group - medium- to dark-gray argillaceous and fossiliferous limestone overlain by yellowish-gray laminated silty limestone. Mapped seperately from the Stone River Group only in Jackson County.
Lithology: limestone
Phyllite undifferentiated (Precambrian-Paleozoic) at surface, covers < 0.1 % of this area
Phyllite undifferentiated
Lithology: phyllite
Chester group (Mississippian) at surface, covers < 0.1 % of this area
Chester group - Limestone, chert, and shale of Meramec, Osage, and Kinderhook age.
Lithology: limestone; chert; shale
Dadeville Complex; Mafic and ultramafic rock (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Mafic and ultramafic rock - ultramafic rock including enstatite pyroxenite, layered actinolite-tremolite amphibolite altered locally to serpentine, anthophyllite, and talc; metanorite; metagabbro; hornblendite; garnet-hornblendite, and massive amphibolite.
Lithology: pyroxenite; amphibolite; hornblendite
Alluvial deposits (Quaternary) at surface, covers < 0.1 % of this area
Alluvial Deposits - Sand, silt, clay, and gravel. In flood plain of Mississippi River more than 100 feet thick; in smaller streams generally less than 20 feet thick.
Lithology: sand; silt; clay or mud; gravel
Chester group (Mississippian) at surface, covers < 0.1 % of this area
Chester group - Sandstone, shale, and limestone.
Lithology: sandstone; shale; limestone
Little Oak and Newala Limestones undifferentiated (Ordovician) at surface, covers < 0.1 % of this area
Little Oak and Newala Limestones undifferentiated - Little Oak Limestone -- dark-gray medium to thick-bedded fossiliferous, argillaceous to silty limestone containing chert nodules. Locally includes thin beds of bentonite in the upper part. Newala Limestone -- light to dark-gray thick-bedded micritic and peloidal limestone and minor dolomite.
Lithology: limestone; chert; bentonite; dolostone (dolomite)
St. Louis Limestone and Warsaw Limestone (Mississippian) at surface, covers < 0.1 % of this area
St. Louis Limestone - Residuum of nodules and blocks of chert in sandy clay. (Originally grayish-brown, medium-bedded limestone.) Maximum preserved thickness about 50 feet. Warsaw Limestone - Residuum of porous chert blocks in sandy clay. (Originally gray, medium- to coarse-grained, thick- bedded limestone.) Thickness about 60 feet.
Lithology: clay or mud; chert
Newala and Longview Limestones undifferentiated (Ordovician) at surface, covers < 0.1 % of this area
Newala and Longview Limestones undifferentiated - light to dark-grey thick-bedded limestone and dolomite, cherty in part.
Lithology: limestone; dolostone (dolomite); chert
Stones River Group; Pierce Limestone and Murfreesboro Limestone (Ordovician) at surface, covers < 0.1 % of this area
Stones River Group; Pierce Limestone - Gray, thin-bedded limestone with shale partings. Thickness 25 feet; and Murfreesboro Limestone - Thick-bedded, dark-gray, fine-grained limestone, with mottlings of magnesian limestone; somewhat cherty in upper part. Maximum exposed thickness 70 feet.
Lithology: limestone; shale
Higgins Ferry Group; Garnet quartzite (garnetite) and garnitiferous altered mafic rock (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Higgins Ferry Group; Garnet quartzite (garnetite) and garnitiferous altered mafic rock.
Lithology: quartzite; metamorphic rock
Poe Bridge Mountain Group (Precambrian to Paleozoic) at surface, covers 0.1 % of this area
Poe Bridge Mountain Group - coarse to fine-grained feldspathic graphite schist, +/- staurolite +/- kyanite +/- sillimanite-muscovite-biotite schist, and garnet-biotite-muscovite schist, and gneiss; locally common pegmatites. Rocks in the area of Turkey Heaven Mountain in Cleburne and Randolph Counties that are here assigned to the Poe Bridge Mountain Group also have been interpreted as part of the Wedowee Group.
Lithology: mica schist; gneiss; pegmatite
Catahoula formation (Miocene) at surface, covers < 0.1 % of this area
Catahoula formation - Irregularly bedded gray sand and sandstone; mottled red and gray, green, and chocolate-colored clay; some quartzite, and some gravel; the Paynes Hammock sand, sandy limestone cross-bedded fine green sand, and thin-bedded sand and clay, is mapped with the underlying Chickasawhay limestone in eastern MS.
Lithology: sand; sandstone; clay or mud; quartzite; gravel
Eutaw Formation (Cretaceous) at surface, covers < 0.1 % of this area
Eutaw Formation - Grayish-green sand, fine-grained, glauconitic, micaceous; interbedded with gray laminated clays which commonly contain carbonized or silicified wood. (Mapped with Coffee except in Hardin County and southeastern Decatur County.) Thickness 0 to 180 feet; thins northward
Lithology: sand; clay or mud
Kahatchee Mountain Group; Sawyer Limestone Member of Brewer Phyllite (Precambrian?-Cambrian?) at surface, covers < 0.1 % of this area
Sawyer Limestone Member of Brewer Phyllite - light to medium-gray argillaceous, silty to siliceous calcite and dolomite marble interbedded with phyllite and quartzite, locally cherty.
Lithology: marble; phyllite; quartzite
Nashville Group; Bigby-Cannon Limestone and Hermitage Formation (Ordovician) at surface, covers < 0.1 % of this area
Nashville Group - Bigby-Cannon Limestone - Brownish-gray phosphatic calcarenite and light-gray to brownish-gray, cryptograined to medium- grained, even-bedded limestone. Thickness 50 to 125 feet; and Hermitage Formation - Thin-bedded to laminated, sandy and argillaceous limestone with shale; nodular shaly limestone; coquina; and phosphatic calcarenite. Thickness 50 to 100 feet.
Lithology: calcarenite; limestone; shale; coquina
Citronelle formation (Pleistocene) at surface, covers < 0.1 % of this area
Citronelle formation - Red sand and gravel and white clay; may be of Pliocene age; the formation mapped is equivalent to the Willis sand and does not include the terrace deposits, colluvium, and residuum commonly considered "Citronelle".
Lithology: sand; gravel; clay or mud
Pride Mountain Formation and Monteagle Limestone undifferentiated (Mississippian) at surface, covers < 0.1 % of this area
Pride Mountain Formation and Monteagle Limestone undifferentiated - Light-gray oolitic limestone, argillaceous and in part bioclastic with interbeds of medium to dark-gray shale.
Lithology: limestone; shale
Jacksons Gap Group; Tallassee Metaquartzite (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Jacksons Gap Group; Tallassee Metaquartzite - medium to fine-grained, massive to thin-bedded quartzite and metaconglomerate and thin beds of graphitic quartz schist, locally contains small garnets.
Lithology: quartzite; meta-conglomerate; schist
Mad Indian Group; Irregular zones of sericite-quartz schist (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Mad Indian Group; Irregular zones of sericite-quartz schist - irregular zones of sericite-quartz schist (+/- garnet) containing finely disseminated graphite, possibly infolded Wedowee Group equivalents. Both mi and migr extensively cut by feldspathic dikes and pegmatites.
Lithology: schist; pegmatite
Bluff Springs Granite (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Bluff Springs Granite - leucocratic quartz diorite (tonalite) to quartz monzonite or trondhjemite, locally foliated.
Lithology: tonalite; quartz monzonite; trondhjemite
Cochran Formation (Cambrian) at surface, covers < 0.1 % of this area
Cochran Formation - poorly sorted arkosic sandstone and conglomerate containing interbedded greenish-gray siltstone and mudstone. The Cochran Formation is exposed only in northeastern Calhoun and northwestern Cleburne Counties.
Lithology: arkose; conglomerate; siltstone; mudstone
Stones River Group; Ridley Limestone (Ordovician) at surface, covers < 0.1 % of this area
Stones River Group; Ridley Limestone - Thick-bedded, brownish-gray limestone, fine-grained, with minor mottlings of magnesian limestone; slightly cherty. Thickness 90 to 150 feet.
Lithology: limestone
Chickamauga Group undivided (Ordovician) at surface, covers < 0.1 % of this area
Chickamauga Group undivided
Lithology: limestone
Tuscaloosa formation (Upper Cretaceous) at surface, covers < 0.1 % of this area
Tuscaloosa formation - Light and vari-colored irregularly bedded sand, clay, and gravel; gravel is mostly in lower portion.
Lithology: sand; clay or mud; gravel
Poe Bridge Mountain Group; Roscoelite-graphite quartz schist and graphitic quartzite (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Poe Bridge Mountain Group; Roscoelite-graphite quartz schist and graphitic quartzite. Rocks in the area of Turkey Heaven Mountain in Cleburne and Randolph Counties that are here assigned to the Poe Bridge Mountain Group also have been interpreted as part of the Wedowee Group.
Lithology: schist; quartzite
Mad Indian Group (Precambrian to Paleozoic) at surface, covers 0.4 % of this area
Mad Indian Group - fine-grained feldspathic biotite gneiss; medium to coarse-grained muscovite-biotite-garnet schist; locally kyanite and sillimanite. Many of the schists have been retrograded to chlorite-garnet-quartz-sericite schist. Both mi and migr extensively cut by feldspathic dikes and pegmatites.
Lithology: felsic gneiss; schist; pegmatite
Biotite Gneiss (Precambrian-Paleozoic) at surface, covers < 0.1 % of this area
Biotite gneiss
Lithology: biotite gneiss
Stream alluvium (Quaternary) at surface, covers < 0.1 % of this area
Stream alluvium and undifferentiated terrace deposits
Lithology: alluvium; alluvial terrace
Motts Gneiss (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Motts Gneiss - leucocratic quartz-rich quartz diorite pencil gneiss.
Lithology: felsic gneiss
Granite Gneiss/ Granite (Precambrian-Paleozoic) at surface, covers < 0.1 % of this area
Granite Gneiss/ Granite
Lithology: granitic gneiss; granite
Dadeville Complex; Waresville Schist (Precambrian to Paleozoic) at surface, covers 0.2 % of this area
Waresville Schist - banded amphibolite interlayered with chlorite schist, chlorite amphibolite, chlorite-actinolite schist, chlorite +/- magnetite quartzite, and actinolite quartzite; may include small ultramafic pods.
Lithology: amphibolite; schist; quartzite; ultramfic intrusive rock
Uchee Complex; Hospilika Granite (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Hospilika Granite - leucocratic, massive epidote-muscovite quartz diorite to granodiorite; weak flow banding, sharp contacts.
Lithology: quartz diorite; granodiorite
Mylonite and ultramylonite (Age not given) at surface, covers < 0.1 % of this area
Mylonite and ultramylonite
Lithology: mylonite
Moffits Mill Schist (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area
Moffits Mill Schist - interlayered biotite-epidote-muscovite-quartz schist, metagraywacke, and quartzite.
Lithology: schist; metasedimentary rock; quartzite

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